This invention relates to mode-locked lasers and, more particularly, to mode-locked lasers which use pulse narrowing and other soliton effects in an optical fiber to control the width and shape of the laser's output pulses.
Extremely short (e.g., picosecond) light pulses are produced by the process of mode-locking in dye, color center, and semiconductor lasers. However, the exact pulse width and shape are not always entirely under complete control. Instead, they are the incompletely understood product of many factors, such as the width and stability of the pump pulses, the gain of the active medium, precise cavity adjustment, and so on. Much effort has been devoted to the development of techniques for further shortening and stabilizing the output pulses. For example, mode-locked dye lasers (operating primarily at visible wavelengths) can be made to produce pulses as short as about 0.1 psec through the introduction of nonlinear absorbers into the cavity, although the resultant output powers are rather weak and problems of stability remain. However, the problem of pulse-width control remains particularly acute at near-infrared wavelengths, in part because of a paucity of suitable nonlinear absorbers in that region of the spectrum.